Xenbase Image ID: 133541

Fig. 4. X-bhh and derived polypeptides modify the anteroposterior pattern of neural gene expression in activin-treated animal caps. Embryos were injected with X-bhh or prolactin RNA and animal cap explants were isolated from blastulae and incubated in the presence or absence of activin. (A) Explants were processed when the sibling embryos reached stage 11, and total RNA was assayed by RT-PCR for the mesodermal markers brachyury (Xbra), goosecoid, and Xwnt-8 and the control EF-1a. Lanes designated plus and minus refer to the presence or absence of reverse transcriptase in the first strand cDNA synthesis. Lanes 1, 2, 5, 6: control animal caps from uninjected embryos. Lanes 3, 4, 7, 8: animal caps from embryos injected with X-bhh. Lanes 9, 10: animal caps from embryos injected with bovine prolactin RNA. Animal caps in lanes 5- 10 were treated with activin A. Note that no mesodermal markers are induced by X-bhh. (B) A second group of explants from the same experiment and in the same order as in A, were cultured until tailbud (stage 25) and assayed for the expression of anteriorposterior neural markers. The actin acted as a control for induction of mesoderm. Expression of anterior neural markers was enhanced by combined treatment with activin and X-bhh relative to either treatment alone; note also the reduction in expression of posterior neural markers by X-bhh in activin-treated explants. (C) In independent experiments, embryos were injected with N or DN-C, and some animal cap explants were treated with activin before culturing until sibling embryos reached tailbud stage. Lanes 1, 2: control animal caps from uninjected embryos. Lanes 3, 4: control animal caps from uninjected embryos, treated with activin. Lanes 5, 6: animal caps from embryos injected with N and treated with activin. Lanes 7, 8: animal caps from embryos injected with DN-C and treated with activin. Whereas N displays activities in activin-treated explants similar to those of X-bhh (see B) DN-C produces the opposite effect, decreasing anterior and increasing posterior neural marker expression. Image published in: Lai CJ et al. (1995) Copyright © 1995. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View

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